The 9th edition of the Nuclear Physics in Astrophysics conference series, NPA IX, was held from September 15 to 20, 2019 at Schloß Waldthausen, which is located about 50 km west of Frankfurt/Main close to Mainz (Germany).It was jointly organized by the Goethe University, Frankfurt, Technical University Darmstadt, Max Planck Institute for Nuclear Physics, Heidelberg and the GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt.The conference series is supported by the Nuclear Physics Division of the European Physical Society. Former conferences of this series were held in Catania (2017), York (2015), Lisbon (2013), Eilat (2011), Frascati (2009), Dresden (2007) and Debrecen (2005, 2002).Every two years the Nuclear Physics in Astrophysics conference brings together researchers from a multi-disciplinary community of experimental and theoretical nuclear physicists, astronomers, astrophysicists and cosmo-chemists to discuss the current challenges of this exciting and fast developing research field.Nuclear physics is the necessary link between astronomical observations, stellar models and galactic chemical evolution. The impressive progress in astrophysics during the last decades explaining and predicting astronomical scenarios was only possible because of the fruitful interplay between all disciplines. New insights in one field triggered new developments in the other fields. New experimental techniques are typically the response to new predictions and observations. Recent success stories involve exotic objects like merging neutron stars, more abundant red giants or even rather ordinary stars as the Sun.The conference has received significant interest amongst the community with 139 participants from all over the world. The scientific program consisted of 65 plenary oral presentations, including 17 invited review talks and 48 contributed talks, as well as 45 poster presentations.We are grateful to P. Descouvemont, R. Hirschi, F. Käppeler, A. Kankainen, M. Lugaro, M. Paul, F. Thielemann and M. Wiescher who served as members of the International Advisory Committee and actively contributed to accomplish a well-balanced scientific program. To our great pleasure, also a considerable number of young students and Postdocs lively participated. The conference speakers and also the colleagues who presented posters gave an impressive performance: Thank you once more!Two evenings were devoted to well-attended poster sessions, which opened the opportunity to discuss a good number of interesting topics in a relaxed atmosphere. Throughout the conference, active discussions during the sessions were continued during coffee and lunch breaks in the sunny weather and the park of the Schloß Waldthausen.The participants also enjoyed the conference excursion conference excursions to Mainz, Frankfurt and GSI. During the conference dinner held at Schloß Waldthausen awards for the three best poster presentations were provided. The winners were E. Holmbeck, F. Schoger and L. Varga. The awards were kindly provided by the Nuclear Physics European Collaboration Committee (NuPECC).Following a long, successful tradition, the conference was preceded by a school preparing new members of the community for the topics of the conference. The WE-Heraeus summer school on: Nuclear Physics in Astrophysics took place September 10-14, 2019 at Max Planck Institute for Nuclear Physics, Heidelberg. We thank N. Christlieb, M. Hanauske, A. Kankainen, A. Karakas, T. Nakamura and G. Rugel, for excellent and well-received lectures.The conference was accompanied by a small CHETEC workshop and followed by the 7th edition of the p-process workshop.The present proceedings contain the majority of the lectures presented and also most of the poster contributions. We appreciate very much the work of the referees who had the laborious task of selecting and judging the papers which finally were accepted for publication, and, likewise, the cooperation of all authors in preparing their manuscripts. We also express our gratitude to the staff of “Journal of Physics: Conference Series” for undertaking the publication of the proceedings of this conference.A special “thank you” is due to the staff of the conference location Schloß Waldthausen for their hospitality and support and to all of the supporters of NPA IX. Without their generous help it would not have been possible to organize the conference in this way.Finally, we would like to thank all helping hands mastering all of the sometimes smaller, sometimes bigger problems that arose during the preparation and the conference itself. In particular, we are very obliged to K. Schäfer, T. Litvinova, G. Weese, K. Al-Khasawneh, L. Bott, B. Brückner, D. Dmytriiev, K. Göbel, D. Kurtulgil, T. Heftrich, M. Reich, H. Schulte, L. Varga, M. Volknandt.The next Nuclear Physics in Astrophysics conference, NPA X, will be jointly organized by the nTOF and ISOLDE collaboration at CERN.The organizers:René Reifarth (Goethe University, Frankfurt, Germany)Almudena Arcones (Technical University Darmstadt, Darmstadt, Germany)Klaus Blaum (Max Planck Institute for Nuclear Physics, Heidelberg, Germany)Yuri A. Litvinov (GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt)